EP 0687050 A2 19951213 - An overcurrent protection apparatus
Title (en)
An overcurrent protection apparatus
Title (de)
Überstromschutz
Title (fr)
Appareil de protection contre la surintensité
Publication
Application
Priority
- EP 90118133 A 19900920
- JP 25787689 A 19891004
Abstract (en)
An overcurrent protection apparatus is provided comprising a current transformer (4) for detecting current in an AC electric line (1). A first rectifier (5) rectifies the output current of the current transformer (4) and a capacitor (12) is coupled across the positive and negative outputs of the first rectifier (5). Circuit breaker means (2, 10) are provided for disconnecting the AC current line. Switching means (25) are coupled across the output terminals of the first current transformer (4). A second rectifier (24) is provided for rectifying the output of a second current transformer (23) connected to the AC electric line (1). A resistor (26) is coupled across the positive and negative outputs of the second rectifier. A reference voltage generator (13) generates a predetermined reference voltage while a pulse signal generator (16) generates a control signal for varying the duty ratio of operation of the switching means (25) in proportion to the voltage across the capacitor (12) when the voltage exceeds the reference voltage value. The circuit breaker means (2, 10) operate to disconnect the AC electric line (1) when the voltage across the resistor (26) exceeds a predetermined value. <IMAGE>
IPC 1-7
IPC 8 full level
H02H 3/08 (2006.01); H02H 1/06 (2006.01); H02H 3/087 (2006.01); H02H 3/093 (2006.01)
CPC (source: EP KR US)
H02H 1/066 (2013.01 - EP US); H02H 3/08 (2013.01 - KR)
Citation (applicant)
US 3818275 A 19740618 - SHIMP A
Designated contracting state (EPC)
CH DE FR GB IT LI
DOCDB simple family (publication)
EP 0421204 A2 19910410; EP 0421204 A3 19920408; EP 0421204 B1 19960821; DE 69028171 D1 19960926; DE 69028171 T2 19970123; EP 0687050 A2 19951213; EP 0687050 A3 19960522; JP H03124215 A 19910527; JP H0710145 B2 19950201; KR 910008905 A 19910531; US 5124875 A 19920623; ZA 906490 B 19910626
DOCDB simple family (application)
EP 90118133 A 19900920; DE 69028171 T 19900920; EP 95113775 A 19900920; JP 25787689 A 19891004; KR 900011162 A 19900723; US 56886390 A 19900817; ZA 906490 A 19900816